Substrate specifity and inhibitors of polyphenol oxidase in aspect of darkening of fresh and frozen mushrooms (Agaricus bisporus (Lange) Sing.)

Activity of mushroom polyphenol oxidase (PPO) toward 6 substrates and inhibitory effect of cysteine, 2-mercaptoethanol, benzoic acid and sodium metabisulphite were determined. The o-diphenols which appeared to be the best substrates were: catechin, DOPA (L-3,4-dihydro-xyphenylalanine) and chlorogcnic acid. Affinity of PPO crude preparation substrates to enzyme, expressed as inverse value of Michaelis constant was lower then affinity of catechol. Inhibitory effect depended on specifity of inhibitors and their concentration. Electrophoretic patterns of PPO of mushrooms reveals slow and fast moving 4 isoforms when DOPA was used as a substrate, 2 bands for catechin and chlorogenic acid while only one band showed activity toward tyrosine and p-cresol.

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Inhibitory effect of melanins from Agaricus bisporus polyphenol oxidase and two different substrates on carboxypeptidases A and B activity

European Food Research and Technology ◽

10.1007/s00217-011-1595-5 ◽

2011 ◽

Vol 233 (6) ◽

pp. 1075-1079 ◽

Cited By ~ 2

Author(s):

Víctor Falguera ◽

Oriol Miarnau ◽

Jordi Pagán ◽

Albert Ibarz

Keyword(s):

Polyphenol Oxidase ◽

Agaricus Bisporus ◽

Inhibitory Effect

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Inhibitory effect of chlorogenic acid on polyphenol oxidase and browning of fresh-cut potatoes

Postharvest Biology and Technology ◽

10.1016/j.postharvbio.2020.111282 ◽

2020 ◽

Vol 168 ◽

pp. 111282

Author(s):

Dai Cheng ◽

Guangliang Wang ◽

Jinlei Tang ◽

Congying Yao ◽

Pengfei Li ◽

...

Keyword(s):

Chlorogenic Acid ◽

Polyphenol Oxidase ◽

Inhibitory Effect ◽

Fresh Cut

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Development of a High-Throughput Method to Study the Inhibitory Effect of Phytochemicals on Trimethylamine Formation

Nutrients ◽

10.3390/nu13051466 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1466

Author(s):

Lisard Iglesias-Carres ◽

Lauren A. Essenmacher ◽

Kathryn C. Racine ◽

Andrew P. Neilson

Keyword(s):

Chlorogenic Acid ◽

Gallic Acid ◽

High Throughput ◽

Anaerobic Fermentation ◽

Inhibitory Effect ◽

Healthy Human ◽

High Throughput Method ◽

Lyase Activity ◽

Inhibitory Potential ◽

Potential Maximum

Choline is metabolized by the gut microbiota into trimethylamine (TMA), the precursor of pro-atherosclerotic molecule trimethylamine N-oxide (TMAO). A reduction in TMA formation has shown cardioprotective effects, and some phytochemicals may reduce TMA formation. This study aimed to develop an optimized, high-throughput anaerobic fermentation methodology to study the inhibition of choline microbial metabolism into TMA by phenolic compounds with healthy human fecal starter. Optimal fermentation conditions were: 20% fecal slurry (1:10 in PBS), 100 µM choline, and 12 h fermentation. Additionally, 10 mM of 3,3-dimethyl-1-butanol (DMB) was defined as a positive TMA production inhibitor, achieving a ~50% reduction in TMA production. Gallic acid and chlorogenic acid reported higher TMA inhibitory potential (maximum of 80–90% TMA production inhibition), with IC50 around 5 mM. Neither DMB nor gallic acid or chlorogenic acid reduced TMA production through cytotoxic effects, indicating mechanisms such as altered TMA-lyase activity or expression.

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Anti-diabetes Constituents in Leaves of Smallanthus sonchifolius

Natural Product Communications ◽

10.1177/1934578x1000500123 ◽

2010 ◽

Vol 5 (1) ◽

pp. 1934578X1000500 ◽

Cited By ~ 3

Author(s):

Xiang Zheng ◽

He Fan ◽

Kang Ting-Guo ◽

Dou De-Qiang ◽

Gai Kuo ◽

...

Keyword(s):

Quality Control ◽

Chlorogenic Acid ◽

Caffeic Acid ◽

Analytical Method ◽

Inhibitory Effect ◽

Hplc Method ◽

Smallanthus Sonchifolius ◽

Rp Hplc

The inhibitory effect of smallanthaditerpenic acids A, B, C and D previously isolated from leaves of Smallanthus sonchifolius (yacon) on α-glucosidase were examined and their IC50 were determined to be 0.48 mg/mL, 0.59 mg/mL, 1.00 mg/mL, and 1.17 mg/mL respectively. In addition, a rapid, reliable RP-HPLC method for the analysis of chlorogenic acid, caffeic acid, and smallanthaditerpenic acids A and C in yacon leaves was established, and the variation in their contents in leaves from plants cultivated in different places and collected at different times of the year were compared. The established analytical method for determining smallanthaditerpenic acids A and C, chlorogenic acid and caffeic acid presented good results and could be used as a method for the quality control of S. sonchifolius leaves.

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Charakterisierung und Kinetik des in der Rattenplacenta vorkommenden mikrosomalen Enzyms, das den Wasserstoff-Transfer von Oestradiol auf Androstendion katalysiert / Characterization and Kinetics of the Microsomal Enzyme of Rat Placenta which Functions as a “Transhydrogenase” between Estradiol-17β and Androstenedione

Zeitschrift für Naturforschung B ◽

10.1515/znb-1971-0715 ◽

1971 ◽

Vol 26 (7) ◽

pp. 710-719 ◽

Cited By ~ 2

Author(s):

Kunhard Pollow ◽

Barbara Pollow

Keyword(s):

Hydrogen Transfer ◽

Microsomal Fraction ◽

Close Relation ◽

Inhibitory Effect ◽

Magnesium Ions ◽

Michaelis Constant ◽

Temperature Optimum ◽

Optimum Ph ◽

Kinetics Of ◽

Estradiol 17Β

The microsomal fraction of rat placenta contains a 17β-hydroxysteroid-oxidoreductase which transfers hydrogen from position 17 of estradiol to androstenedione. This hydrogen transfer is dependent on NAD, NADP as cofactor is without effect. The optimum pH is at 6,9. In the presence of NAD the Michaelis constant for estradiol is 4,17 · 10-5м at pH 7,4. In the presence of androstenedione in the incubation medium the Km-value for estradiol is decreased, which indicates an increased affinity for the enzyme. The temperature optimum of the enzyme is 38 °C. Addition of SH-blocking agents inhibited the enzyme activity. Zinc and magnesium ions had an inhibitory effect on the “transhydrogenase” and B-NADPT specifically labelled from [1-T]-glucose showed that the non-effect of NADP on transhydrogenation from estradiol to androstenedione resulting in reduction of position 17 is not due to different stereospecifity.The results show a close relation between the oxidative metabolism of estradiol and the reduction of androstenedione, indicating that estradiol-17β, as the preferred hydrogen-donating substrate, is an essential component of the androstenedione-hydrogenating system in the microsomal fraction of rat placenta.

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Inhibitory effect of sodium metabisulphite and chlorine on growth of Aspergillus spp. and Penicillium spp. strains isolated from marine shrimp

Ciência Rural ◽

10.1590/s0103-84782013000900029 ◽

2013 ◽

Vol 43 (9) ◽

pp. 1721-1726 ◽

Cited By ~ 2

Author(s):

Ygor Flávio de Moraes Santos ◽

Átyla Peeter Batista Veloso ◽

Rodrigo Maciel Calvet ◽

Maria Marlúcia Gomes Pereira ◽

Carina Maricel Pereyra ◽

...

Keyword(s):

Inhibitory Effect ◽

Shrimp Farming ◽

Penicillium Species ◽

Sodium Metabisulphite ◽

Marine Shrimp ◽

Total Fungi ◽

Frozen Shrimp ◽

Vitro Effect ◽

Penicillium Spp

The sodium metabisulphite (SMB) is used in shrimp farming to prevent melanosis and the 5.0 ppm chlorine (CL) concentration used in the shrimp processing is efficient as a bactericide, but there is no evidence of the effectiveness of these chemical compounds as fungicides. Therefore, the aim of this study was to evaluate the in vitro effect of sodium metabisulphite (SMB) and chlorine (CL) on the growth of Aspergillus and Penicillium species isolated from marine shrimp in different stages of processing. The samples were collected from a frozen shrimp processing industry, located in Piauí State, Brazil. The total fungi and occurrence of Aspergillus and Penicillium species were evaluated. For in vitro sensibility test using the diffusion disk in agar method, five concentrations of SMB (0%, 1%, 3%, 5% and 10%) and six of CL (0, 1, 2, 3, 4 and 5 µg mL-1) were used. The fungal counts in the different processing stages ranged from 1.74 to 3.38 CFU g-1. Twenty-nine Aspergillus strains were isolated, prevailing A. versicolor (59.3%) and twenty-two of Penicillium, prevailing P. citrinum (74%). One strain of A. flavus was AFB1 producer. All the isolated strains of P. citrinum produced citrinin. All tested species were in vitro sensitive to 3% of SMB, except the A. flavus. The 10% concentration of SMB inhibited the in vitro growth of all strains. The CL concentrations tested did not inhibit the studied species growth and SMB concentrations above 3.0% inhibited in vitro the growth of the tested strains.

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